9.1
Method
It
is a long acting low dose, reversible, progestin-only method of
contraception for women. The system contains 6 capsules each measuring
34 mm in length and 2.4 mm in outer diameter containing 36mg crystalline
levonorgestrel. It is effective for up to 5 years after insertion.
9.2 Mechanism of action
The
capsule releases approximately 85 µg of LNG per 24 hours during
the first 6-12 months of use, and 50 µg/day by 9 months and, thereafter,
30 µg/day for the remaining duration of use. There are three probable
mechanisms of action :
• suppresses LH surge necessary for ovulation.
About 10% women ovulate during first 2 years of use and 50% by
5 years. But in the ovulatory cycles there is high incidence of
ovulatory insufficiency
• thickens cervical mucus and decreases
the amount of mucus forming a barrier to sperm penetration
• inhibits endometrial maturation and
causes its atrophy thus preventing implantation
9.3 Advantages
•
rapidly reversible. Ovulatory cycles are restored within the first
month after removal in most women
• highly effective
• continuous method without much effort
or motivation by the user
• not a coitus-related method
• user effectiveness closely approximates
the theoretical effectiveness
• can be inserted 6 weeks post-partum
in lactating women
• no estrogenic side-effects
• prevents iron deficiency anaemia
9.4 Disadvantages
•
weight gain
• breast tenderness
• disruption of menstrual cycles especially
during first year of use
• insertion and removal requires a surgical
procedure by a trained personnel
• higher initial cost as compared to OCPs
and barrier methods
• implant is visible under the skin and
may be unacceptable to users
• offers no protection against STI / HIV
9.5 Contraindications
•
breast-feeding women less than 6 weeks post-partum
• current deep vein thrombosis/pulmonary
embolism
• history of stroke
• current or past history of ischaemic
heart disease
• migraine with focal neurological deficit
• unexplained vaginal bleeding not evaluated
• current and past history of breast cancer
• active hepatitis, liver tumors
• patient on drugs likely to affect metabolism
of LNG eg. - phenytoin, phenobarbitone, rifampicin etc.
9.6 Instructions for use
It
is important to know when to insert a Norplant.
During menstrual cycle
• any time it is certain that woman is
not pregnant. If started within first 7 days of menstrual bleeding
no back-up methods is required.
Post-partum
• breast-feeding mothers as early as 6
weeks post-partum
• non breast-feeding mothers immediately
or any time she desires within 6 weeks post-partum
After spontaneous or induced abortion
• immediately or within first 7 days after
first or second trimester abortion
When stopping other method
• immediately
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